1. Field of the Invention
This invention relates to an electrophotographic photosensitive member, and a process cartridge and an electrophotographic apparatus which have the electrophotographic photosensitive member.
2. Description of the Related Art
As an electrophotographic photosensitive member (hereinafter also simply “photosensitive member”), in view of advantages of low prices and high productivity, an organic electrophotographic photosensitive member has become popular, which has a support and provided thereon a photosensitive layer (organic photosensitive layer) making use of organic materials as photoconductive materials (such as a charge generating material and a charge transporting material). As the organic electrophotographic photosensitive member, one having what is called a multi-layer type photosensitive layer is prevalent, which is a photosensitive layer constituted of a charge generation layer containing a charge generating material such as a photoconductive dye or a photoconductive pigment and a charge transport layer containing a charge transporting material such as a photoconductive polymer or a photoconductive low-molecular weight compound; the layers being superposed to form the photosensitive layer. This is one taking account of advantages such as a high sensitivity and a variety for material designing.
Electrophotographic photosensitive members are commonly used in electrophotographic image forming processes together with developing materials. Electrical external force and mechanical external force are directly applied to the surfaces of the electrophotographic photosensitive members, and hence many problems may arise.
As a problem of such electrophotographic photosensitive members, image deterioration may be given which is caused by scratches made on the electrophotographic photosensitive member surfaces because of the above external force. To solve such a problem, it is actively studied to improve electrophotographic photosensitive member surface layers. Stated specifically, it is attempted to improve the mechanical strength of surface layers in order to improve the durability of photosensitive member surfaces against their scratch and wear that come about because of such external force.
Polycarbonate resin has hitherto widely been used as a binder resin for surface layers of electrophotographic photosensitive members. In recent years, it is proposed that polyarylate resin, which has a higher mechanical strength than the polycarbonate resin, is used so that the surface layers can be improved in mechanical strength (see, e.g., Japanese Patent Application Laid-open No. H10-039521). The polyarylate resin is one of aromatic dicarboxylic acid polyester resins.
Japanese Patent Application Laid-open No. H02-127652 discloses an electrophotographic photosensitive member having as a surface layer a cured layer making use of a curable resin as a binder resin. Japanese Patent Applications Laid-open No. H05-216249 and No. H07-072640 also disclose an electrophotographic photosensitive member having as a surface layer a charge transporting cured layer formed by subjecting monomers to cure polymerization in the presence of energy of heat or light; the monomers being a binder resin monomer having a carbon-carbon double bond and a monomer having a charge transporting function and having a carbon-carbon double bond. Japanese Patent Applications Laid-open No. 2000-066424 and No. 2000-066425 further disclose an electrophotographic photosensitive member having as a surface layer a charge transporting cured layer formed by subjecting a compound to cure polymerization in the presence of energy of electron rays; the compound being a hole transporting compound having a chain-polymerizable functional group in the same molecule.
Thus, in recent years, as techniques by which the mechanical strength of the surfaces of electrophotographic photosensitive members are improved, techniques have been proposed in which a binder resin having a high mechanical strength is used in the surface layers of electrophotographic photosensitive members and in which surface layers are formed as cured layers.
In recent years, a method is also proposed in which the surface of the electrophotographic photosensitive member is appropriately roughened for the purpose of improving the performance in cleaning the photosensitive member surface by means of a cleaning member.
As a method of roughening the surface of the electrophotographic photosensitive member, Japanese Patent Application Laid-open No. S53-092133 discloses a technique in which the surface roughness (roughness of peripheral surface) of the electrophotographic photosensitive member is controlled within a specific range in order to make transfer materials readily separable from the surface of the electrophotographic photosensitive member. This Japanese Patent Application Laid-open No. S53-092133 also discloses a method in which drying conditions in forming a surface layer is controlled to roughen the surface of the electrophotographic photosensitive member in orange peel. Japanese Patent Application Laid-open No. S52-026226 discloses a technique in which the surface layer is incorporated with particles to roughen the surface of the electrophotographic photosensitive member. Japanese Patent Application Laid-open No. S57-094772 discloses a technique in which the surface of a surface layer is sanded with a wire brush made of a metal to roughen the surface of the electrophotographic photosensitive member. Japanese Patent Application Laid-open No. H01-099060 discloses a technique in which specific cleaning device and toner are used to roughen the surface of an organic electrophotographic photosensitive member. According to this Japanese Patent Application Laid-open No. H01-099060, it is described that the problems of turn-up of the cleaning blade and chipping of edges thereof can be solved which may come into question when used in an electrophotographic apparatus having a certain higher process speed.
Japanese Patent Application Laid-open No. H02-139566 discloses a technique in which the surface of a surface layer is sanded with a filmy abrasive to roughen the surface of the electrophotographic photosensitive member. Japanese Patent Application Laid-open No. H02-150850 discloses a technique in which blasting is carried out to roughen the surface of the electrophotographic photosensitive member. This technique, however, is unclear as to details of a surface profile of the electrophotographic photosensitive member surface-roughed by such a method. International Publication No. 2005/93518 pamphlet discloses a technique in which the above blasting is carried out to roughen the peripheral surface of the electrophotographic photosensitive member, and discloses an electrophotographic photosensitive member having a stated dimple profile. It is described therein that improvements have been achieved in regard to smeared images tending to come about in a high-temperature and high-humidity environment and transfer performance of toner. Japanese Patent Application Laid-open No. 2001-066814 also discloses a technique in which the surface of the electrophotographic photosensitive member is processed by compression forming by means of a stamper having unevenness in the form of wells.